pallnet Posted November 15, 2004 Share Posted November 15, 2004 I think I need a few others ideas as to what this could be. First off here is the basic specs of the motor. 8.9-1 compression T3/T4 Greddy Type-S BOV SDS EM3 6E Running 5psi at the moment. This is what's going on.. I'm crusing and I can hear air escaping from the BOV. When the BOV pops, it flutters. If I loosen the tension on the BOV it will hang open alot more. The more I tighten it, the worst the flutter gets. The car will get into boost but I feel like it will get into boost a little quicker if the BOV does not open. I checked the operation of the BOV and it's in perfect working order. I bought the IC setup already madeup and out of a S30. I noticed that the BOV mount is right after the turbo and I thought it was a rule of thumb that the BOV should be as close to the TB as possible. Maybe this is my issue and maybe not. All and any ideas would be helpful.. Thanks.. pallnet Quote Link to comment Share on other sites More sharing options...
yo2001 Posted November 15, 2004 Share Posted November 15, 2004 Do you have the second nipple hooked up? I had mine pretty loose and it never leaked with both the nipples connected. Quote Link to comment Share on other sites More sharing options...
pallnet Posted November 15, 2004 Author Share Posted November 15, 2004 I do not have the second nipple connected. When I test that nipple it's basicly open to the vent horn of the BOV. so I will be loosing boost pressure to the atmosphere. One of the issues with this setup is that that engine normaly makes high vac #'s. I'm getting 22"s of vac at idle and when cruising it's the same.. Most turbo engines make 16 inches of vac at cruising and somewhere around 20 inches at idle. This makes it very easy to set the BOV. Not mine.. I believe that the compression is causeing this. this makes it very hard to set the BOV to pop at the correct time. When i set it to open at the higher vac #'s it flutters badly. if i se the BOV to open and not flutter, it opens the wholetime i'm in the high vac #'s and this happens in cruising. Quote Link to comment Share on other sites More sharing options...
yo2001 Posted November 15, 2004 Share Posted November 15, 2004 The second nipple is made to apply pressure on the back of the diaphram to hold the valve close under boost. I don't remember it leaking under boost. run about 16psi and the flatter will go away. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted November 15, 2004 Share Posted November 15, 2004 Not to thread hijack but since you're attention is already here: Yo2001 just wanted to make sure you saw the thread in the non-tech section regarding DSM crank walk... think you'd get a kick out of it now back to the topic... is BOV flutter a bad thing? Or you just dont' like the sound? I have a stock 1G DSM BOV... I crushed the cap down a tiny bit... was trying to tighten the spring to keep it from leaking at cruise as well, and now on shifts mine flutters instead of that nice 'pssssssssshhh' sound. Mine is recirculated but you can still hear it pretty clearly. For a while I was convinced that the BOV wasn't working (though it will still open at idle so it must be working) and the fluttering sound was compressor surge... thankfully I've seen posts like this mentioning that fluttery noise so I know it's my BOV afterall. Too bad crushing down the cap on the stock BOV's is a one way operation or I'd loosen it back up and let it leak (recirculated) and go back to the nice pssssssssh sound. Another side question... are there aftermarket BOV's (interested in the Greddy Type S in particular) that bolt right up to the stock DSM BOV flange? Quote Link to comment Share on other sites More sharing options...
yo2001 Posted November 15, 2004 Share Posted November 15, 2004 The flutter of BOV is not same as comp. surge. You know comp. surge cause it will damge the thrust bearing fast. Also, DSM BOV flange is not same as Greddy's. Greddy is same as HKS though. (old style) There are some aftermarket BOV for DSM out there and Mitsu makes upgraded BOV that suppose to be better than a 1G BOV. Quote Link to comment Share on other sites More sharing options...
lifegrddude Posted November 15, 2004 Share Posted November 15, 2004 I'm running a Greddy S valve on my setup, and I only get a slight hint of flutter during high boost runs (12psi) and let off. Otherwise all I hear during light cruise and low boost (factory boost) let offs is the blowoff valve. I did have to tighten it a bit from the factory settings (roughly 1 1/4 turns I think) due to the valve opening under boost. I only have one nipple hooked up since mine is not recirculated back into the system. John 82ZXT Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted November 15, 2004 Share Posted November 15, 2004 well I can't say I've ever heard compressor surge so don't know what it sounds like, but the descriptions of surge that I've read seem to describe the sound that I hear from my car pretty well. Having never heard a BOV flutter either, I really can't say for sure WHAT the noise is, but common sense and a few tests suggest it must be the BOV after all. I know for a fact the BOV is still opening under vacuum, and closes if I pull the vac reference off... so it seems to be working correctly and should be relieving pressure before the compressor surges. The only worry I really have is the place I 'chose' to put it... I couldn't think of a good way to mount it close to the TB, so instead it is mounted on the I/C pipes, just after the I/C. I wouldn't THINK the placement of the unit would be enough to cause compressor surge, but... I don't really know enough to know for sure. Quote Link to comment Share on other sites More sharing options...
Z-Gad Posted November 15, 2004 Share Posted November 15, 2004 It sounds like your problem could be right there I do not have the second nipple connected. When I test that nipple it's basicly open to the vent horn of the BOV. so I will be loosing boost pressure to the atmosphere. That "nipple" connection is to open the valve, but only under vacuum conditions. It should be run to your intake manifold, anywhere on the plenum after the throttlebody. When you are under positive pressure (boost), the positive pressure holds the valve closed (so it doesn't leak) until the throttle closes. When you step off the gas, the throttle closes, a vacuum condition occurs in the manifold, that line to the nipple on the BOV valve goes under vacuum as well, and the valve opens, releasing the pressure. Psssssssst!! Quote Link to comment Share on other sites More sharing options...
wigenOut-S30 Posted November 15, 2004 Share Posted November 15, 2004 I have the Greddy type S BOV. I dont have that smaller nipple hooked to anything. Just the larger one on top going to my intake manifold. As for the adjustment I have the set screw down with 4 threds showing.. The bov works perfect. opens and shuts crisp and no flutter and no leaking. Quote Link to comment Share on other sites More sharing options...
Forrest Posted November 15, 2004 Share Posted November 15, 2004 Z-gad, that's the first nipple and he does have that hooked up. The second nipple on the Type-S is hooked to the vacuum line coming from the compressor. Quote Link to comment Share on other sites More sharing options...
ZR8ED Posted November 15, 2004 Share Posted November 15, 2004 If you are running more than usual vac readings, check your timing. My BOV would stay slightly open at idle and cruising. when I'd nail it, I could HEAR the BOV slam shut. It would also slam shut when reving in neutral. (looking directly at the BOV) That is how I figured where the sound was coming from. It turned out my timing was wayyy retarded. A real fluke, as it didn't appear to have manually shifted... ( I did however install a new ecu for what its worth, though it "should" not affect anything) If your timing is OK, then check for a vac leak... Good luck. Quote Link to comment Share on other sites More sharing options...
Z-Gad Posted November 15, 2004 Share Posted November 15, 2004 Ahh, TY for the clarification...perhaps a photo of how it is hooked up might help diagnose... Quote Link to comment Share on other sites More sharing options...
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